Charge forming device



Dec. 1, 1931. F. E. AsELnNE CHARGE FORMING DEVICE Dec. 1, 1931.

F. E. ASELTINE CHARGE vFORMING DEVICE Filed Aug. 25. 1928 2 Sheets-Sheet 2 m .mk

Patented Dec. 1, 1931 UNITED STATES PATENT OFFICE FRED E. ASELTIN E, OF DAYTON, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, T DELGO PRODUCTS CORPORATION, OF DAYTON, OHIO, A CORPORATION OF DELAWARE CHARGE FORMING DEVICE Application filed August 25, 1928.

This invention relates to charge forming devices for internal combustion engines and more particularly to the type ot' charge forming device which comprises a plurality of primary fuel mixing chambers, one for each intake port of the engine, which cooperate respectively with a plurality of secondary mixing chambers located adjacent the said intake ports and receiving primary mixture from pipes connected with the primary carburetors While receiving air when required through the branches of an air manifold having a single air inlet for admitting air to all the secondary mixing chambers. A single fuel reservoir supplies liquid fuel to all of said primary mixing chambers.

Examples of charge forming devices of this character are disclosed in the copending applications ot Wilford H. Teeter, Serial N o. 221,372, tiled September 22, 1927, and Fred E. Aseltine and "ilford H. Teeter, Serial No. 221,371. tiled September 22, 1927.

In prior devices of this type, such as those disclosed yin the above mentioned applications, various means are provided for regulating the proportions of fuel and airin the mixture under different operating conditions, soas to provide'a mixture having the desired proportions to most satisfactorily operate the engine under all conditions of speed and load. Among these mixture proportioning devices is a. dash pot which retards the opening movement of the main air valve on opening of the throttle so as to restrictthe supply of ail; entering the carburetor when said 'throttle is opened for the purpose of enriching the mixture during this period in order to enable the engine to accelerate rapidly and smoothly,- and may be constructed to act as a pump and supply additional fuel to the mixture simultaneously with the restriction of the supply of air. This dash pot is provided with a movable piston and movable cylinder, the latter being operated bythe throttle so that as the throttle is opened the cylinder is operated to increase the resistance of said dash pot. The dash -pot is so constructed that any given movement ofthe throttle results in a given movement of the dash pot cylinder regardless Serial No. 302,053.

of the position of the throttle at the beginning ot' its movement. This results in unsatisfactory engine operation under certain circumstances, because on accelerating from l0 to 25 miles per hour vehicle speed, for instance, it is necessaryv to enrich the mixture to a greater extent than when accelerating from a 40 to 55 miles per hour vehicle speed. However, in the earlier devices referred to, the mixture would be enriched to the same degree in both instances because the throttle movement is the same, resulting in too great enrichment of the mixture under certain conditions of operation and too little under other conditions.

It is accordingly the principal object of the present invention to provide means for enriching the mixture for acceleration on opening movements of the throttle, which is variably ei'ective in accordance with engine suction and the position of the throttle at the time its opening movement begins. More specifically', itI is an object ofthe inventlon to provide means for enriching the mixture on opening movements of the throttle, the effectiveness of which is variably controlled automatically by the engine suction.

'Brieiiyg according to the present invention thse objects are accomplished by providin g mechanical connections of the type disclosed in the prior applications above referred to for lifting the dash pot cylinder as the throttle is opened, including a lever engaging said cylinder, and by providing in addition thereto, means for varying the position of the fulcrum of said leverin accordance with the engine suction at points posterior to the throtaccompanying drawings wherein a preferred embodiment of one form of the present in vention is clearly shown.

In the drawings:

Fig. 1 is a vertical longitudinal section through a charge forming device in which a preferred form of the present invention is embodied.

Fig. 2 is a vertical transverse section on the line 2-2 of Fig. 1.

Fig. 3 is a horizontal section on the line 3-3 of Fig.v2.

Figs. 4 and 5 are side elevations of the carburetor unit looked at from opposite sides.

Fig. 6 is a detail elevation of the primary throttle.

Fig. 7 is ay detail sectionof the fuel pump.

The device disclosed comprises a main air manifold 10 having three outlet branches, the middle branch 12 being shown herein. y Each of these branches communicates with one of the intake ports 14 of a multicylinder engine and each is provided with an attaching flange 16 for securing the manifold to the engine block in the usual manner. Adjacent the inlet of the manifold is provided a flange 18 to which the main carburetor unit is adapted to be' attached, as shown in Fig. 1.

The carburetor unit comprises a main housing 20 having an attaching flange 22 adapted to be secured to the flange 18 by screws 24. An air inlet horn 26 is secured in position t0 register with an opening 28 in the upper wall of the housing 20, in any suitable way. A casting 30 which supports a dash pot cylinder in a manner hereinafter described, and has certain fuel passages formed therein, is secured by screws 32 to a flange 34 projecting from the mainhousing 20. A sheet metal fuel bowl 36 is supported by the casting 3() and is secured thereto in any desirable manner. Fuel is conducted from a main source of supply to the fuel bowl by a conduit which is not shown herein and the flow of fuel to the bowl is controlled by a float 38 operating in the usual manner to maintain a substantially constant level of fuel in said bowl.

Fuel flows from the bowl 36 to a plurality of primary fuel nozzles 40, one of which is located in eachof the. primary mixing chambers 42, the construction of which is briefly described hereinafter. The fuel conduit between the bowl and said nozzles comprises a vertical fuel passage 44 communicating at its -upper end with a horizontal fuel canal 46 porary fuel starving of the engine unless means be provided to prevent such an action. For this purpose va check valve 50 is provided in an enlarged chamber .52 formed at the junction of the fuel passages 44 and 46 and -on reduction of the mixing chamber suction said valve seats on the bottom of said chamber preventing any downward flow of fuel. A two-stage metering valve 54 is received in the vertical fuel passage 44 as indicated in Fig. 2 and is fully described in the above mentioned applications.

Each fuel nozzle 40 is provided with a main fuel outlet 56 inthe top of said nozzle and a secondary fuel outlet comprising two small orifices. 58 and 60 in the vertical wall of the nozzle near thebottom ofthe mixing chamber. At relatively high speeds the mixing chamber suction is sufficient to lift fuel from the main outlet 56 as well as from the orifices 58 and 60. During idling or low speed operation under load, however, the suction is sufficient to lift fuel only to some point between the top ofthe nozzle and the ori- ,fices 58 and 60, fuel then. flowing from these orifices by the action of gravity. Each nozzle is provided with a restricted fuel metering orifice 6,2@ The primary mixing chambers are enlarged chainbersjnto which the nozzles project, formed in the'anterior ends of primary mixture passages 64 .which are parallel to each other and' relatively close together, as4 indicated in Fig. 2, and when the carburetor is attached to the manifold these passages register with` conduits 'which convey the primary mixture to the secondary mixing chambers in the manner disclosed in the above mentioned applications. The middle one of these primary mixture passages communicates with a tube 66 secured in the middle branch 12 of the manifoldand which conveys the primary mixture to the secondary mixing chamber associated with that particular manifold branch.

Substantially all the air entering the cai'- buretor flows through the air horn 26 and is controlled by a main air valve 70, normally held against aseat 72 by a spring 74, received between the valve and the flange 76, projecting from a sleeve 78, slidably mounted on a stationary guide sleeve 80, which is fixed in the housing 20 and serves as a guide sleeve for the stem 82 to which the air valve is secured, as well as for the sliding sleeve 78. When it is desired to choke the carburctors to facilitate starting of the engine, the flange 76 is adapted to be lifted, by means of the arm 83, until the upper end of the sleeve 78 engages the valve to hold it closed, as fully disclosed in the above applications. Sullicient air to carry the starting fuel from the nozzles to the engine intake ports is admitted through a slot 84 formed in a plate 86 secured to the housinU.20, as shown in Fig. 1.

The valve controls the admission of air 'I to a main air chamber 88 from which air flows to the primary mixture passages through an orifice 90 in the floor of said air chamber and to the secondary mixing chambers through a passage 92 which communicates with the inlet of the manifold 10. A manually operable throttle 94, secured to a shaft 96 journalled in the main housing 20, controls the passage of air through said passage 92 and is operated concurrently with the primary throttle by means hereinafter described in detail.

A single primary throttle 97 extends across all of the primary mixture passages so as to control the flow therethrough and is provided with grooves 98 which register with said passages. This throttle is journallcd for rotation in the housing 20 which is provided with a groove 100 which cooperates with a screw 102 to prevent any longitudinal movement of said throttle.

On opening of either or both the throttls, the suction in the air chamber 88 is increased and the air valve is opened against the tension of the spring to ladmit additional air. The opening of this valve is retarded to some extent, however, to enrich the mixture for purposes of acceleration and to prevent fluttering of said valve, by means of a liquid dash pot. This dash pot comprises a. cylinder 110 located within the fuel bowl 36 and'cooperating with a piston 112 secured in any desirable manner to the lower end of the air valve stem 82. The cylinder' 110 is vertically slidable in a guide 114 cast integral with the frame 30. The guide 114 and the cylinder 110 are provided with orices 116 and 118 respectively to admit fuel to the cylinder from the fuel bowl 36. The cylinder is provided with a by-pass pipe 120,-as shown in Fig. 2, for the purpose of producing a variable retarding effect in accordance with the position of the dash pot piston relative to the cylinder 110. The by-pass pipe is received in a notch 122 in the guide 114 when the cylinder is lifted as hereinbefore described and the cooperationof these parts prevents turning of the cylinder relative to the guide, but permits vertical movement thereof.

According to the present invention, the dash pot cylinder is notI vonly adapt-ed to be lifted on opening of the throttle in the manner set forth in the earlier copending applications previously referred to, but means are also provided to regulate the distance through which the cylinder is lifted in accordance with the manifold suction, which varies as the throttle is moved to different positions. This automatically controlledlifting mechanism comprisesa bifurcated lever indicated in its entirety by the number 130 and having two ar 132 provided with( lugs 134 which are adziiied to engage in a groove 136 formed in 'the outer surface of the cylinder at its upper end. The lever 130 is fixed on agock shaft 138 rotatably mounted in the frame 30 and having secured to one end thereof, outside of the carburetor unit as shown in Fig.

4, an operating arm 140. This arm is provided with an arcuate slot 142, in which is received the horizontally projecting lower end 143 of an operating link 144 provided with nuts 145, or other suitable means to prevent disengagement of the link and slot. The upper end of link 144 is pivotally connected in any suitable manner at 146 to the free end of a 4lever 148, pivoted on the main housing 20 at 150. The arcuate slot 142 is concentric relative to the pivot 146 so that any pivotal movement of the operating link 144 varies the position of the lower end of said link relative to the operating varm 140, but is ineffective to move said arm. The lever 148 is adapted to be operated by means of a cam 152, secured to the spindle 154 integral with and projecting from one end of the primary throttle 97. As the throttle is opened the cam 152 moves the lever 148 downwardly moving the arm 140 downwardly or counter-clockwise and simultaneously mov-ing the arms 132 upwardly or clockwise in Fig. 1 to lift the cylinder 110.

The degree of movement imparted to the cylinder depends on the effective length of the lever arm 140. Then the link 144 is positioned, as shown in Fig. 4, with the lower end thereof positioned near the shaft 138, the cylinder is given its .maximum lift and as the arm 144 is moved toward the end of the slot 142 the distance through which the cylinder is lifted decreases. the arm 144 is controlled in accordance with the engine suction and to this end said arm is connected at its lower end to link 156, the other end of which is pivotally connected to the lower end of an arm 158, which is pivoted on-a pin 160 projecting from the main housing 20. Connected to the arm 158 at some point between the ends thereof is an operating link 162, slidably received in a support 164 which is secured to the main housing 20; and at its opposite end, the link 162 is connected to one end of an expansible bellows or sylphon 166 which is secured to-and supported by a plate 167 extending upwardly from andcast integral with the frame 30, as indicated in the Fig. 4; A suction pipe 168 communicates with the passage 92 ata point immediately in advance of the throttle 94 and at its opposite end is connected to a union 170 threaded onto'the plate 167, or other suitable coupling means, so that said suction pipe communicates with the interior of the above mentioned bellows.

p Then the engine is not running and no suction is communicated to said bellows, a spring 172' surrounding the operating link 162 and received between the support 164 and a collar 174 secured to said link is effective to hold the parts in position shown in Fig. 5, in which The position of position the bellows is expanded and the link 144 is moved as far as possible to the left in Fig. 4. When the engine is started and is operated at low speed with the throttles nearly closed, the suction at points posterior to the throttle 94 will lbe greater than under any other operatingA condition and the bellows will be collapsed as indicated in Fig. 4. In this position opening of the-throttle will give the greatest possible lift to the cylinder 110.

If either or both of the throttles 94 and 97 f occupy a partially open position, the suction at points posterior togthrottle 94 isrless than when the throttles are substantially closed. In this position of the throttles, the bellows is partially expanded so that the force of the spring 172 is balanced by the suction eifective on the sylphon and the arm 158 has been movedn a clockwise direction, moving the lower end of the link 144 to the left Vin Fig. 4. A further opening movement of either or both throttles will, therefore, result in a lesser lifting movement of cylinder 110. The suction on the engine side of saidthrottle is progressively reduced as the throttles approach fullopen position so that the more nearly'opensaid throttles are at the begin- A ning of any opening movement, the nearer the link 144 will be to the left end of slot 142 in Fig. 4 and the less will be the lifting move-v ment of cylinder 110 on an opening movement of said-throttles. This will-result in a greater retardation ofthe opening movement of the air valve Whenever the throttle is opened from a nearly closed position than when it is opened from a wider open position. e

The throttle valves 94 and 97 are adapted to be operated by a common operating mech'- anism comprising a main operating lever 180, secured to a spindle 181 projecting from the y primary throttle-97 and which' is pivotally connected by a screw 182 with an operating link 184, which is provided witha slot 186v operatingl arm 180 is moved. in a lClockwise direction. 1n Fig. 5 the mechanism is in its normal position correspondingrespectively to the idling position of the throttle 97 and thev fully closed position of thel throttle 94:J

. 'I he operating arm 180 is held -inthis position by means of the operating connection which extends, to'a point convenient to the operator ofthe vehicle and the spring 194 tends to move the-ar1n190 in 'a clockwise dif rectvion and, therefore, holds the throttle 94 closed. I-n this position screw 200 is adapted to. engage the stud 188 and by adjustment of said screw, the idling position of the throttle 98 may be determined. When the arm 180 is moved counter-clockwise in Fig. 5, the first part of its movement only moves the throttle mixing chambers are identical and only one of such mixing chambers is illustrated herein. v Each comprises a Venturi tube 210 clamped between the manifold and engine block and positioned so that theoutlet of the primary mixture conduit associated therewith terminates at the point of greatest suction in the Venturi tube. These Venturi tubes to be associated with the above described dash pot and operated on opening of the throttle to aid inthe formation of the rich mixture` necessary during the acceleration period. To this end the cylinder 110 is provided within thefuel bowl with an outlet pipe 220 con:

`nected with a valve seat member 222 normally closed by a ball valve 224 held in closed position by a spring 226 which is received within a fitting 228 attached to the valve seat member. A delivery conduit 230 is connected to said iitting in any desirable manner and ico may be connected to the mixture passage to deliver fuel thereto fat any desired point therein. It will also be understood that this pump may be omitted if desired and enrichment of the mixture accomplished solely by restricting the flow of entering air during the opening ofthe throttle.

While the form of embodiment of the present inventionas herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all 4coming within the scope of the claims which follow.

t What is claimed is as follows:

1. A charge forming device for internal combustion' engines 'com rising a mixture passage, means for supp ying fuel and air thereto, a throttle, an air-valve controlling admission of air to said vmixing chamber, means for enriching thelmixture on opening movements of the throttle comprising a dash pot forretarding theopeningof said valve, means .for increasing the resistance ofthe dash pot as the throttle is o ened,l and means for varying the effect of said last mentioned means in accordance with variations in manifold vacuum.

2. A charge forming device for internal combustion engines comprising a mixture `its opening movement.

passage, means for supplying the fuel and air thereto, a throttle, an air valve controlling admission of air to said mixing chamber, means for enriching the mixture on opening movements of the throttle comprising a dash pot for retarding the opening of said valve, means for increasing the resistance of the dash pot as the throttle is opened, and means for varying the effect of said last mentioned means in accordance with the position of the throttle at the beginning of its opening movement.

3. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle, an air valve controlling admission of air to said mixing chamber, means for enriching the mixture on opening movements of the throttle comprising a dash pot for retarding the opening of said valve, means for increasing the resistance of the dash pot as the throttle is opened, and suction operated means for varying the effect of said last mentioned means.

4. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle, an air valve controlling admission of air to said mixing chamber, means for enriching the mixture on opening movements of the throttle comprising a dash pot for retarding the opening of said valve, means for increasing the resistance of the dash pot as the throttle is opened, means operated by the throttle for enriching the mixture as thethrottle is opened, and means for varying the effect of said enriching means in accordance with the manifold vacuum.

5. A charge forming device for internal combustion engines comprising' a mixture passage, means for supplying fuel and air thereto, a throttle, an air valve controlling admission of air to said mixing chamber, means operated by the throttle for enriching the mixture as the throttle is opened, and suction operated means for variably controlling the action of said enriching means.

6. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle, an air valve controlling admissionof air to said mixing chamber, means operated by the throttle for enriching the mixture as the throttle is opened, and means for variably controlling the action of said enriching means in accordance with the position of the throttle at the beginning of 7 A charge forming device for internal combustion engines comprising a m1xture assafre means for su l ino fuel and air thereto, a throttle, an air valve controlling admission of air to said mixing chamber, means operated by the throttle for'enriching the mixture as the throttle is opened, and

suction operated means for variably controlling the action of said enriching means in accordance with the position of the throttle at the beginning of its opening movement.

8. A Icharge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle, an air valve controlling admission of air to said mixing chamber, mixture enriching means comprising means for retarding the opening movement of the air valve on opening movements of the throttle and for simultaneously injecting additional fuel into the mixture passage to enrich the mixture for acceleration and means for varying the effect of the mixture enriching means in accordance with the position of the throttle at the beginning of its movement.

9. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle, an air valve controlling admission of air to said mixing chamber, means for retarding the opening movement of the air valve on opening movements of the throttle and for simultaneously injecting additional fuel into the mixture passage to enrich the mixture for acceleration and means for varying the effect of the mixture enriching means in accordance with the manifold vacuum. i

10. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle, an air valve controlling admission of air to said mixing chamber, means for retarding the opening movement of the air valve on opening movements of the throttle and for simultaneously injecting additional fuel into the mixture passage to enrich the mixture for acceleration and suction operated means for varying the effect of the mixture enriching means in accordance with the position of the throttle at the beginning of its movement.

11. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle` an air valve controlling admission of air to said mixing chamber, a dash pot for retarding the opening of the air valve, means operated by said throttle during opening movements thereof to move air valve, means operated by said throttle during opening movements thereof to move the cylinder of said dash pot relative to the piston to increase the retarding effect of said dash pot and means for varying the movements of said cylinder in accordance with the position of the throttle at the beginning of its opening movement.

13. A charge forming device for internal combustion engines comprising a mixture passage, means for supplying fuel and air thereto, a throttle, an air valve controlling admission of air to said mixing chamber, a dash pot for retarding the opening of the air valve, means operated by said throttle during opening movements thereof to move the cylinder of said dash pot relative to the piston to increase the retarding effect of said dash pot and suction operated means for varying the movements of said cylinder in accordance With" the position of the throttle at the beginning of its opening movement.

14. A charge forming device for internal combustion engmes comprising a mixture passage, means for supplying fuel and air thereto, a throttle, an air valve controlling admission of air to said mixing chamber, a dash pot for retarding the opening of the air valve, means operable on opening movements of the throttle to increase the resistance of the dash'pot so as to enrich the mixture for acceleration, a pressure responsive element for varying the eect of said last meny tioned means, and a suction connection extending from said element to the mixture passage in advance of the throttle.

l5. A charge forming devicefor multicylinder engines comprising a plurality of secondary mixing chambers, a plurality of primary mixing chambers delivering fuel mixture thereto, means for supplying fuel and air to said primary mixing chambers, an air valve controlling the supply of air to all said mixing chambers, a throttle, a dash pot for retarding the opening of said air valve, means operable on opening of the throttle to increase the retarding effect of the dash pot enriching the mixture in all of said mixing chambers, and means for varying the effect of said last mentioned means in accordance with the manifold vacuum.

In testimony whereof I hereto affix my signature.

FRED E. ASELTINE. 

